( function () {
/**
 * @fileoverview LightningStrike object for creating lightning strikes and voltaic arcs.
 *
 *
 * Usage
 *
 * var myRay = new LightningStrike( paramsObject );
 * var myRayMesh = new THREE.Mesh( myRay, myMaterial );
 * scene.add( myRayMesh );
 * ...
 * myRay.update( currentTime );
 *
 * The "currentTime" can vary its rate, go forwards, backwards or even jump, but it cannot be negative.
 *
 * You should normally leave the ray position to (0, 0, 0). You should control it by changing the sourceOffset and destOffset parameters.
 *
 *
 * LightningStrike parameters
 *
 * The paramsObject can contain any of the following parameters.
 *
 * Legend:
 * 'LightningStrike' (also called 'ray'): An independent voltaic arc with its ramifications and defined with a set of parameters.
 * 'Subray': A ramification of the ray. It is not a LightningStrike object.
 * 'Segment': A linear segment piece of a subray.
 * 'Leaf segment': A ray segment which cannot be smaller.
 *
 *
 * The following parameters can be changed any time and if they vary smoothly, the ray form will also change smoothly:
 *
 * @param {Vector3} sourceOffset The point where the ray starts.
 *
 * @param {Vector3} destOffset The point where the ray ends.
 *
 * @param {double} timeScale The rate at wich the ray form changes in time. Default: 1
 *
 * @param {double} roughness From 0 to 1. The higher the value, the more wrinkled is the ray. Default: 0.9
 *
 * @param {double} straightness From 0 to 1. The higher the value, the more straight will be a subray path. Default: 0.7
 *
 * @param {Vector3} up0 Ray 'up' direction at the ray starting point. Must be normalized. It should be perpendicular to the ray forward direction but it doesn't matter much.
 *
 * @param {Vector3} up1 Like the up0 parameter but at the end of the ray. Must be normalized.
 *
 * @param {double} radius0 Radius of the main ray trunk at the start point. Default: 1
 *
 * @param {double} radius1 Radius of the main ray trunk at the end point. Default: 1
 *
 * @param {double} radius0Factor The radius0 of a subray is this factor times the radius0 of its parent subray. Default: 0.5
 *
 * @param {double} radius1Factor The radius1 of a subray is this factor times the radius1 of its parent subray. Default: 0.2
 *
 * @param {minRadius} Minimum value a subray radius0 or radius1 can get. Default: 0.1
 *
 *
 * The following parameters should not be changed after lightning creation. They can be changed but the ray will change its form abruptly:
 *
 * @param {boolean} isEternal If true the ray never extinguishes. Otherwise its life is controlled by the 'birthTime' and 'deathTime' parameters. Default: true if any of those two parameters is undefined.
 *
 * @param {double} birthTime The time at which the ray starts its life and begins propagating. Only if isEternal is false. Default: None.
 *
 * @param {double} deathTime The time at which the ray ends vanishing and its life. Only if isEternal is false. Default: None.
 *
 * @param {double} propagationTimeFactor From 0 to 1. Lifetime factor at which the ray ends propagating and enters the steady phase. For example, 0.1 means it is propagating 1/10 of its lifetime. Default: 0.1
 *
 * @param {double} vanishingTimeFactor From 0 to 1. Lifetime factor at which the ray ends the steady phase and begins vanishing. For example, 0.9 means it is vanishing 1/10 of its lifetime. Default: 0.9
 *
 * @param {double} subrayPeriod Subrays cycle periodically. This is their time period. Default: 4
 *
 * @param {double} subrayDutyCycle From 0 to 1. This is the fraction of time a subray is active. Default: 0.6
 *
 *
 * These parameters cannot change after lightning creation:
 *
 * @param {integer} maxIterations: Greater than 0. The number of ray's leaf segments is 2**maxIterations. Default: 9
 *
 * @param {boolean} isStatic Set to true only for rays which won't change over time and are not attached to moving objects (Rare case). It is used to set the vertex buffers non-dynamic. You can omit calling update() for these rays.
 *
 * @param {integer} ramification Greater than 0. Maximum number of child subrays a subray can have. Default: 5
 *
 * @param {integer} maxSubrayRecursion Greater than 0. Maximum level of recursion (subray descendant generations). Default: 3
 *
 * @param {double} recursionProbability From 0 to 1. The lower the value, the less chance each new generation of subrays has to generate new subrays. Default: 0.6
 *
 * @param {boolean} generateUVs If true, the ray geometry will have uv coordinates generated. u runs along the ray, and v across its perimeter. Default: false.
 *
 * @param {Object} randomGenerator Set here your random number generator which will seed the THREE.SimplexNoise and other decisions during ray tree creation.
 * It can be used to generate repeatable rays. For that, set also the noiseSeed parameter, and each ray created with that generator and seed pair will be identical in time.
 * The randomGenerator parameter should be an object with a random() function similar to Math.random, but seedable.
 * It must have also a getSeed() method, which returns the current seed, and a setSeed( seed ) method, which accepts as seed a fractional number from 0 to 1, as well as any other number.
 * The default value is an internal generator for some uses and Math.random for others (It is non-repeatable even if noiseSeed is supplied)
 *
 * @param {double} noiseSeed Seed used to make repeatable rays (see the randomGenerator)
 *
 * @param {function} onDecideSubrayCreation Set this to change the callback which decides subray creation. You can look at the default callback in the code (createDefaultSubrayCreationCallbacks)for more info.
 *
 * @param {function} onSubrayCreation This is another callback, more simple than the previous one. It can be used to adapt the form of subrays or other parameters once a subray has been created and initialized. It is used in the examples to adapt subrays to a sphere or to a plane.
 *
 *
*/

class LightningStrike extends THREE.BufferGeometry {
  constructor(rayParameters = {}) {
    super();
    this.type = 'LightningStrike'; // Set parameters, and set undefined parameters to default values

    this.init(LightningStrike.copyParameters(rayParameters, rayParameters)); // Creates and populates the mesh

    this.createMesh();
  }

  static createRandomGenerator() {
    const numSeeds = 2053;
    const seeds = [];

    for (let i = 0; i < numSeeds; i++) {
      seeds.push(Math.random());
    }

    const generator = {
      currentSeed: 0,
      random: function () {
        const value = seeds[generator.currentSeed];
        generator.currentSeed = (generator.currentSeed + 1) % numSeeds;
        return value;
      },
      getSeed: function () {
        return generator.currentSeed / numSeeds;
      },
      setSeed: function (seed) {
        generator.currentSeed = Math.floor(seed * numSeeds) % numSeeds;
      }
    };
    return generator;
  }

  static copyParameters(dest = {}, source = {}) {
    const vecCopy = function (v) {
      if (source === dest) {
        return v;
      } else {
        return v.clone();
      }
    };

    dest.sourceOffset = source.sourceOffset !== undefined ? vecCopy(source.sourceOffset) : new THREE.Vector3(0, 100, 0), dest.destOffset = source.destOffset !== undefined ? vecCopy(source.destOffset) : new THREE.Vector3(0, 0, 0), dest.timeScale = source.timeScale !== undefined ? source.timeScale : 1, dest.roughness = source.roughness !== undefined ? source.roughness : 0.9, dest.straightness = source.straightness !== undefined ? source.straightness : 0.7, dest.up0 = source.up0 !== undefined ? vecCopy(source.up0) : new THREE.Vector3(0, 0, 1);
    dest.up1 = source.up1 !== undefined ? vecCopy(source.up1) : new THREE.Vector3(0, 0, 1), dest.radius0 = source.radius0 !== undefined ? source.radius0 : 1, dest.radius1 = source.radius1 !== undefined ? source.radius1 : 1, dest.radius0Factor = source.radius0Factor !== undefined ? source.radius0Factor : 0.5, dest.radius1Factor = source.radius1Factor !== undefined ? source.radius1Factor : 0.2, dest.minRadius = source.minRadius !== undefined ? source.minRadius : 0.2, // These parameters should not be changed after lightning creation. They can be changed but the ray will change its form abruptly:
    dest.isEternal = source.isEternal !== undefined ? source.isEternal : source.birthTime === undefined || source.deathTime === undefined, dest.birthTime = source.birthTime, dest.deathTime = source.deathTime, dest.propagationTimeFactor = source.propagationTimeFactor !== undefined ? source.propagationTimeFactor : 0.1, dest.vanishingTimeFactor = source.vanishingTimeFactor !== undefined ? source.vanishingTimeFactor : 0.9, dest.subrayPeriod = source.subrayPeriod !== undefined ? source.subrayPeriod : 4, dest.subrayDutyCycle = source.subrayDutyCycle !== undefined ? source.subrayDutyCycle : 0.6; // These parameters cannot change after lightning creation:

    dest.maxIterations = source.maxIterations !== undefined ? source.maxIterations : 9;
    dest.isStatic = source.isStatic !== undefined ? source.isStatic : false;
    dest.ramification = source.ramification !== undefined ? source.ramification : 5;
    dest.maxSubrayRecursion = source.maxSubrayRecursion !== undefined ? source.maxSubrayRecursion : 3;
    dest.recursionProbability = source.recursionProbability !== undefined ? source.recursionProbability : 0.6;
    dest.generateUVs = source.generateUVs !== undefined ? source.generateUVs : false;
    dest.randomGenerator = source.randomGenerator, dest.noiseSeed = source.noiseSeed, dest.onDecideSubrayCreation = source.onDecideSubrayCreation, dest.onSubrayCreation = source.onSubrayCreation;
    return dest;
  }

  update(time) {
    if (this.isStatic) return;

    if (this.rayParameters.isEternal || this.rayParameters.birthTime <= time && time <= this.rayParameters.deathTime) {
      this.updateMesh(time);

      if (time < this.subrays[0].endPropagationTime) {
        this.state = LightningStrike.RAY_PROPAGATING;
      } else if (time > this.subrays[0].beginVanishingTime) {
        this.state = LightningStrike.RAY_VANISHING;
      } else {
        this.state = LightningStrike.RAY_STEADY;
      }

      this.visible = true;
    } else {
      this.visible = false;

      if (time < this.rayParameters.birthTime) {
        this.state = LightningStrike.RAY_UNBORN;
      } else {
        this.state = LightningStrike.RAY_EXTINGUISHED;
      }
    }
  }

  init(rayParameters) {
    // Init all the state from the parameters
    this.rayParameters = rayParameters; // These parameters cannot change after lightning creation:

    this.maxIterations = rayParameters.maxIterations !== undefined ? Math.floor(rayParameters.maxIterations) : 9;
    rayParameters.maxIterations = this.maxIterations;
    this.isStatic = rayParameters.isStatic !== undefined ? rayParameters.isStatic : false;
    rayParameters.isStatic = this.isStatic;
    this.ramification = rayParameters.ramification !== undefined ? Math.floor(rayParameters.ramification) : 5;
    rayParameters.ramification = this.ramification;
    this.maxSubrayRecursion = rayParameters.maxSubrayRecursion !== undefined ? Math.floor(rayParameters.maxSubrayRecursion) : 3;
    rayParameters.maxSubrayRecursion = this.maxSubrayRecursion;
    this.recursionProbability = rayParameters.recursionProbability !== undefined ? rayParameters.recursionProbability : 0.6;
    rayParameters.recursionProbability = this.recursionProbability;
    this.generateUVs = rayParameters.generateUVs !== undefined ? rayParameters.generateUVs : false;
    rayParameters.generateUVs = this.generateUVs; // Random generator

    if (rayParameters.randomGenerator !== undefined) {
      this.randomGenerator = rayParameters.randomGenerator;
      this.seedGenerator = rayParameters.randomGenerator;

      if (rayParameters.noiseSeed !== undefined) {
        this.seedGenerator.setSeed(rayParameters.noiseSeed);
      }
    } else {
      this.randomGenerator = LightningStrike.createRandomGenerator();
      this.seedGenerator = Math;
    } // Ray creation callbacks


    if (rayParameters.onDecideSubrayCreation !== undefined) {
      this.onDecideSubrayCreation = rayParameters.onDecideSubrayCreation;
    } else {
      this.createDefaultSubrayCreationCallbacks();

      if (rayParameters.onSubrayCreation !== undefined) {
        this.onSubrayCreation = rayParameters.onSubrayCreation;
      }
    } // Internal state


    this.state = LightningStrike.RAY_INITIALIZED;
    this.maxSubrays = Math.ceil(1 + Math.pow(this.ramification, Math.max(0, this.maxSubrayRecursion - 1)));
    rayParameters.maxSubrays = this.maxSubrays;
    this.maxRaySegments = 2 * (1 << this.maxIterations);
    this.subrays = [];

    for (let i = 0; i < this.maxSubrays; i++) {
      this.subrays.push(this.createSubray());
    }

    this.raySegments = [];

    for (let i = 0; i < this.maxRaySegments; i++) {
      this.raySegments.push(this.createSegment());
    }

    this.time = 0;
    this.timeFraction = 0;
    this.currentSegmentCallback = null;
    this.currentCreateTriangleVertices = this.generateUVs ? this.createTriangleVerticesWithUVs : this.createTriangleVerticesWithoutUVs;
    this.numSubrays = 0;
    this.currentSubray = null;
    this.currentSegmentIndex = 0;
    this.isInitialSegment = false;
    this.subrayProbability = 0;
    this.currentVertex = 0;
    this.currentIndex = 0;
    this.currentCoordinate = 0;
    this.currentUVCoordinate = 0;
    this.vertices = null;
    this.uvs = null;
    this.indices = null;
    this.positionAttribute = null;
    this.uvsAttribute = null;
    this.simplexX = new THREE.SimplexNoise(this.seedGenerator);
    this.simplexY = new THREE.SimplexNoise(this.seedGenerator);
    this.simplexZ = new THREE.SimplexNoise(this.seedGenerator); // Temp vectors

    this.forwards = new THREE.Vector3();
    this.forwardsFill = new THREE.Vector3();
    this.side = new THREE.Vector3();
    this.down = new THREE.Vector3();
    this.middlePos = new THREE.Vector3();
    this.middleLinPos = new THREE.Vector3();
    this.newPos = new THREE.Vector3();
    this.vPos = new THREE.Vector3();
    this.cross1 = new THREE.Vector3();
  }

  createMesh() {
    const maxDrawableSegmentsPerSubRay = 1 << this.maxIterations;
    const maxVerts = 3 * (maxDrawableSegmentsPerSubRay + 1) * this.maxSubrays;
    const maxIndices = 18 * maxDrawableSegmentsPerSubRay * this.maxSubrays;
    this.vertices = new Float32Array(maxVerts * 3);
    this.indices = new Uint32Array(maxIndices);

    if (this.generateUVs) {
      this.uvs = new Float32Array(maxVerts * 2);
    } // Populate the mesh


    this.fillMesh(0);
    this.setIndex(new THREE.Uint32BufferAttribute(this.indices, 1));
    this.positionAttribute = new THREE.Float32BufferAttribute(this.vertices, 3);
    this.setAttribute('position', this.positionAttribute);

    if (this.generateUVs) {
      this.uvsAttribute = new THREE.Float32BufferAttribute(new Float32Array(this.uvs), 2);
      this.setAttribute('uv', this.uvsAttribute);
    }

    if (!this.isStatic) {
      this.index.usage = THREE.DynamicDrawUsage;
      this.positionAttribute.usage = THREE.DynamicDrawUsage;

      if (this.generateUVs) {
        this.uvsAttribute.usage = THREE.DynamicDrawUsage;
      }
    } // Store buffers for later modification


    this.vertices = this.positionAttribute.array;
    this.indices = this.index.array;

    if (this.generateUVs) {
      this.uvs = this.uvsAttribute.array;
    }
  }

  updateMesh(time) {
    this.fillMesh(time);
    this.drawRange.count = this.currentIndex;
    this.index.needsUpdate = true;
    this.positionAttribute.needsUpdate = true;

    if (this.generateUVs) {
      this.uvsAttribute.needsUpdate = true;
    }
  }

  fillMesh(time) {
    const scope = this;
    this.currentVertex = 0;
    this.currentIndex = 0;
    this.currentCoordinate = 0;
    this.currentUVCoordinate = 0;
    this.fractalRay(time, function fillVertices(segment) {
      const subray = scope.currentSubray;

      if (time < subray.birthTime) {
        //&& ( ! this.rayParameters.isEternal || scope.currentSubray.recursion > 0 ) ) {
        return;
      } else if (this.rayParameters.isEternal && scope.currentSubray.recursion == 0) {
        // Eternal rays don't propagate nor vanish, but its subrays do
        scope.createPrism(segment);
        scope.onDecideSubrayCreation(segment, scope);
      } else if (time < subray.endPropagationTime) {
        if (scope.timeFraction >= segment.fraction0 * subray.propagationTimeFactor) {
          // Ray propagation has arrived to this segment
          scope.createPrism(segment);
          scope.onDecideSubrayCreation(segment, scope);
        }
      } else if (time < subray.beginVanishingTime) {
        // Ray is steady (nor propagating nor vanishing)
        scope.createPrism(segment);
        scope.onDecideSubrayCreation(segment, scope);
      } else {
        if (scope.timeFraction <= subray.vanishingTimeFactor + segment.fraction1 * (1 - subray.vanishingTimeFactor)) {
          // Segment has not yet vanished
          scope.createPrism(segment);
        }

        scope.onDecideSubrayCreation(segment, scope);
      }
    });
  }

  addNewSubray()
  /*rayParameters*/
  {
    return this.subrays[this.numSubrays++];
  }

  initSubray(subray, rayParameters) {
    subray.pos0.copy(rayParameters.sourceOffset);
    subray.pos1.copy(rayParameters.destOffset);
    subray.up0.copy(rayParameters.up0);
    subray.up1.copy(rayParameters.up1);
    subray.radius0 = rayParameters.radius0;
    subray.radius1 = rayParameters.radius1;
    subray.birthTime = rayParameters.birthTime;
    subray.deathTime = rayParameters.deathTime;
    subray.timeScale = rayParameters.timeScale;
    subray.roughness = rayParameters.roughness;
    subray.straightness = rayParameters.straightness;
    subray.propagationTimeFactor = rayParameters.propagationTimeFactor;
    subray.vanishingTimeFactor = rayParameters.vanishingTimeFactor;
    subray.maxIterations = this.maxIterations;
    subray.seed = rayParameters.noiseSeed !== undefined ? rayParameters.noiseSeed : 0;
    subray.recursion = 0;
  }

  fractalRay(time, segmentCallback) {
    this.time = time;
    this.currentSegmentCallback = segmentCallback;
    this.numSubrays = 0; // Add the top level subray

    this.initSubray(this.addNewSubray(), this.rayParameters); // Process all subrays that are being generated until consuming all of them

    for (let subrayIndex = 0; subrayIndex < this.numSubrays; subrayIndex++) {
      const subray = this.subrays[subrayIndex];
      this.currentSubray = subray;
      this.randomGenerator.setSeed(subray.seed);
      subray.endPropagationTime = THREE.MathUtils.lerp(subray.birthTime, subray.deathTime, subray.propagationTimeFactor);
      subray.beginVanishingTime = THREE.MathUtils.lerp(subray.deathTime, subray.birthTime, 1 - subray.vanishingTimeFactor);
      const random1 = this.randomGenerator.random;
      subray.linPos0.set(random1(), random1(), random1()).multiplyScalar(1000);
      subray.linPos1.set(random1(), random1(), random1()).multiplyScalar(1000);
      this.timeFraction = (time - subray.birthTime) / (subray.deathTime - subray.birthTime);
      this.currentSegmentIndex = 0;
      this.isInitialSegment = true;
      const segment = this.getNewSegment();
      segment.iteration = 0;
      segment.pos0.copy(subray.pos0);
      segment.pos1.copy(subray.pos1);
      segment.linPos0.copy(subray.linPos0);
      segment.linPos1.copy(subray.linPos1);
      segment.up0.copy(subray.up0);
      segment.up1.copy(subray.up1);
      segment.radius0 = subray.radius0;
      segment.radius1 = subray.radius1;
      segment.fraction0 = 0;
      segment.fraction1 = 1;
      segment.positionVariationFactor = 1 - subray.straightness;
      this.subrayProbability = this.ramification * Math.pow(this.recursionProbability, subray.recursion) / (1 << subray.maxIterations);
      this.fractalRayRecursive(segment);
    }

    this.currentSegmentCallback = null;
    this.currentSubray = null;
  }

  fractalRayRecursive(segment) {
    // Leave recursion condition
    if (segment.iteration >= this.currentSubray.maxIterations) {
      this.currentSegmentCallback(segment);
      return;
    } // Interpolation


    this.forwards.subVectors(segment.pos1, segment.pos0);
    let lForwards = this.forwards.length();

    if (lForwards < 0.000001) {
      this.forwards.set(0, 0, 0.01);
      lForwards = this.forwards.length();
    }

    const middleRadius = (segment.radius0 + segment.radius1) * 0.5;
    const middleFraction = (segment.fraction0 + segment.fraction1) * 0.5;
    const timeDimension = this.time * this.currentSubray.timeScale * Math.pow(2, segment.iteration);
    this.middlePos.lerpVectors(segment.pos0, segment.pos1, 0.5);
    this.middleLinPos.lerpVectors(segment.linPos0, segment.linPos1, 0.5);
    const p = this.middleLinPos; // Noise

    this.newPos.set(this.simplexX.noise4d(p.x, p.y, p.z, timeDimension), this.simplexY.noise4d(p.x, p.y, p.z, timeDimension), this.simplexZ.noise4d(p.x, p.y, p.z, timeDimension));
    this.newPos.multiplyScalar(segment.positionVariationFactor * lForwards);
    this.newPos.add(this.middlePos); // Recursion

    const newSegment1 = this.getNewSegment();
    newSegment1.pos0.copy(segment.pos0);
    newSegment1.pos1.copy(this.newPos);
    newSegment1.linPos0.copy(segment.linPos0);
    newSegment1.linPos1.copy(this.middleLinPos);
    newSegment1.up0.copy(segment.up0);
    newSegment1.up1.copy(segment.up1);
    newSegment1.radius0 = segment.radius0;
    newSegment1.radius1 = middleRadius;
    newSegment1.fraction0 = segment.fraction0;
    newSegment1.fraction1 = middleFraction;
    newSegment1.positionVariationFactor = segment.positionVariationFactor * this.currentSubray.roughness;
    newSegment1.iteration = segment.iteration + 1;
    const newSegment2 = this.getNewSegment();
    newSegment2.pos0.copy(this.newPos);
    newSegment2.pos1.copy(segment.pos1);
    newSegment2.linPos0.copy(this.middleLinPos);
    newSegment2.linPos1.copy(segment.linPos1);
    this.cross1.crossVectors(segment.up0, this.forwards.normalize());
    newSegment2.up0.crossVectors(this.forwards, this.cross1).normalize();
    newSegment2.up1.copy(segment.up1);
    newSegment2.radius0 = middleRadius;
    newSegment2.radius1 = segment.radius1;
    newSegment2.fraction0 = middleFraction;
    newSegment2.fraction1 = segment.fraction1;
    newSegment2.positionVariationFactor = segment.positionVariationFactor * this.currentSubray.roughness;
    newSegment2.iteration = segment.iteration + 1;
    this.fractalRayRecursive(newSegment1);
    this.fractalRayRecursive(newSegment2);
  }

  createPrism(segment) {
    // Creates one triangular prism and its vertices at the segment
    this.forwardsFill.subVectors(segment.pos1, segment.pos0).normalize();

    if (this.isInitialSegment) {
      this.currentCreateTriangleVertices(segment.pos0, segment.up0, this.forwardsFill, segment.radius0, 0);
      this.isInitialSegment = false;
    }

    this.currentCreateTriangleVertices(segment.pos1, segment.up0, this.forwardsFill, segment.radius1, segment.fraction1);
    this.createPrismFaces();
  }

  createTriangleVerticesWithoutUVs(pos, up, forwards, radius) {
    // Create an equilateral triangle (only vertices)
    this.side.crossVectors(up, forwards).multiplyScalar(radius * LightningStrike.COS30DEG);
    this.down.copy(up).multiplyScalar(-radius * LightningStrike.SIN30DEG);
    const p = this.vPos;
    const v = this.vertices;
    p.copy(pos).sub(this.side).add(this.down);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    p.copy(pos).add(this.side).add(this.down);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    p.copy(up).multiplyScalar(radius).add(pos);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    this.currentVertex += 3;
  }

  createTriangleVerticesWithUVs(pos, up, forwards, radius, u) {
    // Create an equilateral triangle (only vertices)
    this.side.crossVectors(up, forwards).multiplyScalar(radius * LightningStrike.COS30DEG);
    this.down.copy(up).multiplyScalar(-radius * LightningStrike.SIN30DEG);
    const p = this.vPos;
    const v = this.vertices;
    const uv = this.uvs;
    p.copy(pos).sub(this.side).add(this.down);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    uv[this.currentUVCoordinate++] = u;
    uv[this.currentUVCoordinate++] = 0;
    p.copy(pos).add(this.side).add(this.down);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    uv[this.currentUVCoordinate++] = u;
    uv[this.currentUVCoordinate++] = 0.5;
    p.copy(up).multiplyScalar(radius).add(pos);
    v[this.currentCoordinate++] = p.x;
    v[this.currentCoordinate++] = p.y;
    v[this.currentCoordinate++] = p.z;
    uv[this.currentUVCoordinate++] = u;
    uv[this.currentUVCoordinate++] = 1;
    this.currentVertex += 3;
  }

  createPrismFaces(vertex
  /*, index*/
  ) {
    const indices = this.indices;
    vertex = this.currentVertex - 6;
    indices[this.currentIndex++] = vertex + 1;
    indices[this.currentIndex++] = vertex + 2;
    indices[this.currentIndex++] = vertex + 5;
    indices[this.currentIndex++] = vertex + 1;
    indices[this.currentIndex++] = vertex + 5;
    indices[this.currentIndex++] = vertex + 4;
    indices[this.currentIndex++] = vertex + 0;
    indices[this.currentIndex++] = vertex + 1;
    indices[this.currentIndex++] = vertex + 4;
    indices[this.currentIndex++] = vertex + 0;
    indices[this.currentIndex++] = vertex + 4;
    indices[this.currentIndex++] = vertex + 3;
    indices[this.currentIndex++] = vertex + 2;
    indices[this.currentIndex++] = vertex + 0;
    indices[this.currentIndex++] = vertex + 3;
    indices[this.currentIndex++] = vertex + 2;
    indices[this.currentIndex++] = vertex + 3;
    indices[this.currentIndex++] = vertex + 5;
  }

  createDefaultSubrayCreationCallbacks() {
    const random1 = this.randomGenerator.random;

    this.onDecideSubrayCreation = function (segment, lightningStrike) {
      // Decide subrays creation at parent (sub)ray segment
      const subray = lightningStrike.currentSubray;
      const period = lightningStrike.rayParameters.subrayPeriod;
      const dutyCycle = lightningStrike.rayParameters.subrayDutyCycle;
      const phase0 = lightningStrike.rayParameters.isEternal && subray.recursion == 0 ? -random1() * period : THREE.MathUtils.lerp(subray.birthTime, subray.endPropagationTime, segment.fraction0) - random1() * period;
      const phase = lightningStrike.time - phase0;
      const currentCycle = Math.floor(phase / period);
      const childSubraySeed = random1() * (currentCycle + 1);
      const isActive = phase % period <= dutyCycle * period;
      let probability = 0;

      if (isActive) {
        probability = lightningStrike.subrayProbability; // Distribution test: probability *= segment.fraction0 > 0.5 && segment.fraction0 < 0.9 ? 1 / 0.4 : 0;
      }

      if (subray.recursion < lightningStrike.maxSubrayRecursion && lightningStrike.numSubrays < lightningStrike.maxSubrays && random1() < probability) {
        const childSubray = lightningStrike.addNewSubray();
        const parentSeed = lightningStrike.randomGenerator.getSeed();
        childSubray.seed = childSubraySeed;
        lightningStrike.randomGenerator.setSeed(childSubraySeed);
        childSubray.recursion = subray.recursion + 1;
        childSubray.maxIterations = Math.max(1, subray.maxIterations - 1);
        childSubray.linPos0.set(random1(), random1(), random1()).multiplyScalar(1000);
        childSubray.linPos1.set(random1(), random1(), random1()).multiplyScalar(1000);
        childSubray.up0.copy(subray.up0);
        childSubray.up1.copy(subray.up1);
        childSubray.radius0 = segment.radius0 * lightningStrike.rayParameters.radius0Factor;
        childSubray.radius1 = Math.min(lightningStrike.rayParameters.minRadius, segment.radius1 * lightningStrike.rayParameters.radius1Factor);
        childSubray.birthTime = phase0 + currentCycle * period;
        childSubray.deathTime = childSubray.birthTime + period * dutyCycle;

        if (!lightningStrike.rayParameters.isEternal && subray.recursion == 0) {
          childSubray.birthTime = Math.max(childSubray.birthTime, subray.birthTime);
          childSubray.deathTime = Math.min(childSubray.deathTime, subray.deathTime);
        }

        childSubray.timeScale = subray.timeScale * 2;
        childSubray.roughness = subray.roughness;
        childSubray.straightness = subray.straightness;
        childSubray.propagationTimeFactor = subray.propagationTimeFactor;
        childSubray.vanishingTimeFactor = subray.vanishingTimeFactor;
        lightningStrike.onSubrayCreation(segment, subray, childSubray, lightningStrike);
        lightningStrike.randomGenerator.setSeed(parentSeed);
      }
    };

    const vec1Pos = new THREE.Vector3();
    const vec2Forward = new THREE.Vector3();
    const vec3Side = new THREE.Vector3();
    const vec4Up = new THREE.Vector3();

    this.onSubrayCreation = function (segment, parentSubray, childSubray, lightningStrike) {
      // Decide childSubray origin and destination positions (pos0 and pos1) and possibly other properties of childSubray
      // Just use the default cone position generator
      lightningStrike.subrayCylinderPosition(segment, parentSubray, childSubray, 0.5, 0.6, 0.2);
    };

    this.subrayConePosition = function (segment, parentSubray, childSubray, heightFactor, sideWidthFactor, minSideWidthFactor) {
      // Sets childSubray pos0 and pos1 in a cone
      childSubray.pos0.copy(segment.pos0);
      vec1Pos.subVectors(parentSubray.pos1, parentSubray.pos0);
      vec2Forward.copy(vec1Pos).normalize();
      vec1Pos.multiplyScalar(segment.fraction0 + (1 - segment.fraction0) * (random1() * heightFactor));
      const length = vec1Pos.length();
      vec3Side.crossVectors(parentSubray.up0, vec2Forward);
      const angle = 2 * Math.PI * random1();
      vec3Side.multiplyScalar(Math.cos(angle));
      vec4Up.copy(parentSubray.up0).multiplyScalar(Math.sin(angle));
      childSubray.pos1.copy(vec3Side).add(vec4Up).multiplyScalar(length * sideWidthFactor * (minSideWidthFactor + random1() * (1 - minSideWidthFactor))).add(vec1Pos).add(parentSubray.pos0);
    };

    this.subrayCylinderPosition = function (segment, parentSubray, childSubray, heightFactor, sideWidthFactor, minSideWidthFactor) {
      // Sets childSubray pos0 and pos1 in a cylinder
      childSubray.pos0.copy(segment.pos0);
      vec1Pos.subVectors(parentSubray.pos1, parentSubray.pos0);
      vec2Forward.copy(vec1Pos).normalize();
      vec1Pos.multiplyScalar(segment.fraction0 + (1 - segment.fraction0) * ((2 * random1() - 1) * heightFactor));
      const length = vec1Pos.length();
      vec3Side.crossVectors(parentSubray.up0, vec2Forward);
      const angle = 2 * Math.PI * random1();
      vec3Side.multiplyScalar(Math.cos(angle));
      vec4Up.copy(parentSubray.up0).multiplyScalar(Math.sin(angle));
      childSubray.pos1.copy(vec3Side).add(vec4Up).multiplyScalar(length * sideWidthFactor * (minSideWidthFactor + random1() * (1 - minSideWidthFactor))).add(vec1Pos).add(parentSubray.pos0);
    };
  }

  createSubray() {
    return {
      seed: 0,
      maxIterations: 0,
      recursion: 0,
      pos0: new THREE.Vector3(),
      pos1: new THREE.Vector3(),
      linPos0: new THREE.Vector3(),
      linPos1: new THREE.Vector3(),
      up0: new THREE.Vector3(),
      up1: new THREE.Vector3(),
      radius0: 0,
      radius1: 0,
      birthTime: 0,
      deathTime: 0,
      timeScale: 0,
      roughness: 0,
      straightness: 0,
      propagationTimeFactor: 0,
      vanishingTimeFactor: 0,
      endPropagationTime: 0,
      beginVanishingTime: 0
    };
  }

  createSegment() {
    return {
      iteration: 0,
      pos0: new THREE.Vector3(),
      pos1: new THREE.Vector3(),
      linPos0: new THREE.Vector3(),
      linPos1: new THREE.Vector3(),
      up0: new THREE.Vector3(),
      up1: new THREE.Vector3(),
      radius0: 0,
      radius1: 0,
      fraction0: 0,
      fraction1: 0,
      positionVariationFactor: 0
    };
  }

  getNewSegment() {
    return this.raySegments[this.currentSegmentIndex++];
  }

  copy(source) {
    super.copy(source);
    this.init(LightningStrike.copyParameters({}, source.rayParameters));
    return this;
  }

  clone() {
    return new this.constructor(LightningStrike.copyParameters({}, this.rayParameters));
  }

}

LightningStrike.prototype.isLightningStrike = true; // Ray states

LightningStrike.RAY_INITIALIZED = 0;
LightningStrike.RAY_UNBORN = 1;
LightningStrike.RAY_PROPAGATING = 2;
LightningStrike.RAY_STEADY = 3;
LightningStrike.RAY_VANISHING = 4;
LightningStrike.RAY_EXTINGUISHED = 5;
LightningStrike.COS30DEG = Math.cos(30 * Math.PI / 180);
LightningStrike.SIN30DEG = Math.sin(30 * Math.PI / 180);

THREE.LightningStrike = LightningStrike;
} )();
